bug 745379 - mistake in spdy/2 spec reversed actual priority values r=honzab

netwerk/protocol/http/SpdySession.h

@@ -91,10 +91,19 @@ public:
   const static PRUint8 kFlag_Data_UNI  = 0x02;
   const static PRUint8 kFlag_Data_ZLIB = 0x02;
   
-  const static PRUint8 kPri00   = 0x00;
-  const static PRUint8 kPri01   = 0x40;
-  const static PRUint8 kPri02   = 0x80;
-  const static PRUint8 kPri03   = 0xC0;
+  // The protocol document for v2 specifies that the
+  // highest value (3) is the highest priority, but in
+  // reality 0 is the highest priority. 
+  //
+  // Draft 3 notes here https://sites.google.com/a/chromium.org/dev/spdy/spdy-protocol/
+  // are the best guide to the mistake. Also see
+  // GetLowestPriority() and GetHighestPriority() in spdy_framer.h of
+  // chromium source.
+
+  const static PRUint8 kPri00   = 0 << 6; // highest
+  const static PRUint8 kPri01   = 1 << 6;
+  const static PRUint8 kPri02   = 2 << 6;
+  const static PRUint8 kPri03   = 3 << 6; // lowest
 
   enum
   {

netwerk/protocol/http/SpdyStream.cpp

@@ -325,8 +325,6 @@ SpdyStream::ParseHttpRequestHeaders(const char *buf,
   memset (mTxInlineFrame + 12, 0, 4);
 
   // Priority flags are the C0 mask of byte 16.
-  // From low to high: 00 40 80 C0
-  // higher raw priority values are actually less important
   //
   // The other 6 bits of 16 are unused. Spdy/3 will expand
   // priority to 4 bits.
@@ -336,13 +334,13 @@ SpdyStream::ParseHttpRequestHeaders(const char *buf,
   // receive windows, separate from their spdy priority
   //
   if (mPriority >= nsISupportsPriority::PRIORITY_LOW)
-    mTxInlineFrame[16] = SpdySession::kPri00;
-  else if (mPriority >= nsISupportsPriority::PRIORITY_NORMAL)
-    mTxInlineFrame[16] = SpdySession::kPri01;
-  else if (mPriority >= nsISupportsPriority::PRIORITY_HIGH)
-    mTxInlineFrame[16] = SpdySession::kPri02;
-  else
     mTxInlineFrame[16] = SpdySession::kPri03;
+  else if (mPriority >= nsISupportsPriority::PRIORITY_NORMAL)
+    mTxInlineFrame[16] = SpdySession::kPri02;
+  else if (mPriority >= nsISupportsPriority::PRIORITY_HIGH)
+    mTxInlineFrame[16] = SpdySession::kPri01;
+  else
+    mTxInlineFrame[16] = SpdySession::kPri00;
 
   mTxInlineFrame[17] = 0;                         /* unused */